The asymmetric unit of the title compound, [Ag3Yb(C5HN2O4)2(H2O)2]n, contains three AgI ions, one YbIII ion, two imidazole-4,5-dicarboxylate ligands and two coordinating water molecules. The YbIII atom is eight-coordinated, in a bicapped trigonal prismatic coordination geometry, by six O atoms from three imidazole-4,5-dicarboxylate ligands and two coordinating water molecules. The two-coordinated AgI ions exhibit three types of coordination environments. One AgI atom is bonded to two N atoms from two different imidazole-4,5-dicarboxylate ligands. The other two AgI atoms are each coordinated by one O atom and one N atom from two different imidazole-4,5-dicarboxylate ligands. These metal coordination units are connected by bridging imidazole-4,5-dicarboxylate ligands, generating a two-dimensional heterometallic layer. These layers are stacked along the a axis via O—H⋯O hydrogen-bonding interactions to generate a three-dimensional framework.